Reading Rotary Encoder on Arduino « Circuits@Home

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Sparkfun2010AutonomousVehicleCompetition DigitalcameracontrolusingArduinoUSBHostShield.Part1basics.

RotaryencoderconnectedtoArduino

ReadingrotaryencoderonArduinoByOlegMazurov

Quadraturerotaryencoders,alsoknownasrotarypulsegenerators,arepopularinputdevicesforembeddedplatforms,includingArduino.SeveralrotaryencodercodeexamplesarepostedonArduinositeandelsewhere,however,theytreatencoderasapairofswitches,addingdecoding/debouncingoverhead.Formanyyears,IusedanalgorithmbasedonthefactthatquadratureencoderisaGraycodegeneratorandiftreatedassuch,canbereadreliablyin3straightstepwithoutneedfordebouncing.Asaresult,thecodeImusingisveryfastandsimple,worksverywellwithcheaplowqualityencoders,butissomewhatcrypticanddifficulttounderstand.SoonafterpostingoneofmyprojectswhereIusedrotaryencodertosetmotorspeedistartedreceivingemailsaskingtoexplainthecode.ThisarticleisasummaryofmyrepliesImpresentingsmallexamplewrittenforthepurposeofillustratingmymethod.Imalsogoingthroughthecodehighlightingimportantparts.

Thehardwaresetupcanbeseenontitlepicture.TheencoderfromSparkfunisconnectedtoavintageAtmega168basedArduinoPro.Commonpinoftheencoderisconnectedtoground,pinsAandBareconnectedtopins14and15,AKAAnalogpins0and1,configuredasdigitalinputs.WealsoneedaserialconnectiontothePCtoreceivepower,programtheArduino,andsendprogramoutputtotheterminal.Forthispurpose,SparkfunFTDIbasicbreakoutisused.

Connectingencoderpinstopins0and1of8bitMCUportmakesencoderreadingcodeverysimple.Ifanalogpinsareneededforsomethingelse,itispossibletomoveencodertodigitalpins8,9or0,1(losingserialport)withnomodificationofcodelogic.Whiletechnicallyusinganytwoconsecutiveportpinsispossiblewithabitoftweaking,usingnonconsecutivepinsforencoderinputwiththismethodisnotrecommended.Lastly,itsometimeshardtodeterminewhichencoderpinisAandwhichisBitiseasiertoconnectthematrandomandifdirectioniswrong,swapthepins.

Examplecodeispostedbelow.ItiscompletesketchyoucancopyitfromthispageandpasteintoArduinoIDEwindow,compile,uploadandrun.Theresultofrotatingtheencodercanbeseeninterminalwindow.Notethatserialspeedinthesketchissetto115200,youwillneedtosetyourPCterminaltothatspeedaswell.Theexplanationofthecodeisgivenafterthelisting.

12345678910111213141516171819

/*Rotaryencoderreadexample*/#defineENC_A14#defineENC_B15#defineENC_PORTPINCvoidsetup(){/*Setupencoderpinsasinputs*/pinMode(ENC_A,INPUT);digitalWrite(ENC_A,HIGH);pinMode(ENC_B,INPUT);digitalWrite(ENC_B,HIGH);Serial.begin(115200);Serial.println("Start");}voidloop(){staticuint8_tcounter=0;//thisvariablewillbechangedbyencoderinput



2021222324252627282930313233343536373839

int8_ttmpdata;/**/tmpdata=read_encoder();if(tmpdata){Serial.print("Countervalue:");Serial.println(counter,DEC);counter+=tmpdata;}}/*returnschangeinencoderstate(1,0,1)*/int8_tread_encoder(){staticint8_tenc_states[]={0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0};staticuint8_told_AB=0;/**/old_AB



Rotaryencodersingingoutoftune

Inorderforthismethodtoworkwell,read_encoder()functionneedstobecalledfairlyoften.Toseewhathappenswhenloopisslow,lowerserialportspeedgotoline13,change115200to9600,recompilethesketchandrun(dontforgettoreconfiguretheterminalonPCside).Pictureontheleftshowstheresult.Notethatencodergoesdownfrom237to229,thenjumpsupto230,thencontinuesgoingdown.Sometimesitcountscorrectlybutgives2or3statesperclickinsteadof4.Instabilitieslikethisaregoodindicationofslowloop.Ifencoderisusedtothingslikesettingmotorspeedorsoundvolume,thisbehaviorwontdomuchharmbecauseencoderwillneverskipbackmorethanonestateandoverallcountingwouldstillbeintherightdirection.However,ifencoderisusedforinterfacingwithdisplay,glitcheslikethatareveryannoying.Therefore,foruserinterfaceapplications,looptimeshouldbekeptshortandinsomecasesitmaybeevennecessarytoconvertencoderreadingfunctionintointerruptserviceroutine.Giventhesizeandspeedofencoderreadfunction,suchconversioncanbedone

withoutmuchdifficulty.

Tosummarize:Ipresentedamethodtoconvertquadraturerotaryencoderoutputintodirectioninformationusinglookuptable.Themethodmakesdebouncingunnecessary,andasaresult,conversionfunctionimplementedwiththismethodisveryshort,fast,andworksverywellonsmall8bitMCUplatforms,suchasArduino.

Oleg.[EDIT]IpostedanewarticledescribingreadinganencoderfromanISR.

Relatedposts:

1. Vigoriusstirringredefined.Part2electronics

April12th,2010|Tags:Arduino,rotaryencoder,sketch|Category:Arduino,MCU,programming|224comments

224commentstoReadingrotaryencoderonArduino

OlderComments 1 2 3

gabriellaNovember9,2012at11:39amReply

Okthanksalotthatisreallyhelpful.ButassoonasIintegratedthiscodewithsomemorecomplexcodeIhaveusingpulseIn()functiontounderstandtheinputofastandardRCreceiver,andamotordriver

controllingtwomotors,theencoderseemstotallyincorrect:WhenIhadthethesamefunctionsworkingontheencoder,Iwasgettingsupercleanvalues.ButwhenIhadmorecodeandtheencoderstuffrunningsidebyside,mycountervaluesaretotallyoff(seebelow,whenspinningtheencoderroundandround).SoitseemslikethetimingistotallynotworkingImwonderingwhatImightbedoingwrongbecausenothingtoohighlevelishappeninginmycode,andItookoutallmyprintlns.

Icanattachmycodeifthatdbehelpful,butwaswonderingyourthoughts/experience(reusing2encoderswithsomeotherprocessesgoingoninArduinoUNO)Thankyousosomuchagainforallthehelpandexplanation.

ReadyCountervalue2:0Countervalue2:255Countervalue2:0Countervalue2:255Countervalue2:0Countervalue2:255Countervalue2:0Countervalue2:255Countervalue2:0



Countervalue2:255Countervalue2:254Countervalue2:253Countervalue2:254Countervalue2:253Countervalue2:252Countervalue2:251Countervalue2:252Countervalue2:251Countervalue2:252Countervalue2:251Countervalue2:252Countervalue2:251Countervalue2:252Countervalue2:251Countervalue2:252Countervalue2:253Countervalue2:252Countervalue2:251Countervalue2:252Countervalue2:251Countervalue2:250

olegNovember9,2012at11:49amReply

Thecodeyouveaddedisblockingsomewhere.Youneedtoeitherfixitorswitchtointerruptdrivenencoderreading,likethisone>https://www.circuitsathome.com/mcu/rotaryencoderinterrupt

serviceroutineforavrmicros

gabriellaNovember9,2012at12:13pmReply

Hm.YeaIcommentedeverythingoutandtheencodersworkgreat.WhenIaddbackinstufftoreadthereceiver,thatsthepointatwhichtheencodersseemtostopworking:

Channel2Value=pulseIn(RX1,HIGH,20000)//readRCchannel2

Channel1Value=pulseIn(RX3,HIGH,20000)//readRCchannel2//Serial.print(motor_body:)

Imwonderingwhatyoumeanbythecodeisblockingsomewhereorwhatafixwouldbe??

Thanksalotagain

olegNovember9,2012at12:50pmReply

Blockingiswhenapieceofcodeiswaitingforsomeeventtohappen,interruptingtheflowofexecutionofthemainloop.Forexample,delay()isblockingtheprogramwontcontinueuntil

timespecifiedasdelayhasexpired.Ifyouhaveadelayofonesecondinyourmainloop,youcanrotateyourencoderfullcircleandmisseverypulse.

Fixingmeansfindingblockingcodeandwritingitdifferently.Whatdoes20000meaninpulseIn?

gabriellaNovember9,2012at5:25pmReply

OkIguessIhavetouseaninterrupt?IwantedtobeabletouseArduinoUNOwiththetwoencoders.WouldtherebeawaytousetwoencoderswithArduinoUNO,evenifthetwodefaultinteruptpinsare2



and3?thethirdparameter(20000)isthetimeoutinmicroseconds.

justfyi,PulseIN():Readsapulse(eitherHIGHorLOW)onapin.Forexample,ifvalueisHIGH,pulseIn()waitsforthepintogoHIGH,startstiming,thenwaitsforthepintogoLOWandstopstiming.Returnsthelengthofthepulseinmicroseconds.Givesupandreturns0ifnopulsestartswithinaspecifiedtimeout.soitseemstheproblemisitdelaysandwaits(ieblocking)


Yes,tryinterruptcodeandseeifitworksforyou.Thecodeusesinterruptonchange,youcanconfigureanypintobeasourceofthisinterrupt.

KyleRassweilerNovember15,2012at12:22amReply

Iwaswonderingwhyyouneededatimeoutof2000?Wouldtheserialnotstillworkfinewithout?(Ithinkthattimeoutmaybeanexampleofblocking).

SteffanoGizzlerNovember30,2012at3:23pmReply

HiOleg

Ireallyappreciateyourtutorials,theyaregreatandamwonderingifyoucouldputmeintherightdirectionasIambuildingabidirectionalpeoplesensorandcounterinaroomusingtwoinfraredsensors(S1andS2).WhatIwantisthefirstsequenceonbreakingS1andS2thechangeshouldsignalentryandincrementacounterwhilstbreakingthebeaminthesecondsequenceS2firstandS1willsignalexitanddecrementacounteranddisplaythecountvalueona3digit7segmentdisplay.Ihavethoughtofusingtheideaofreadingtworotaryencoderusingexternalinterruptsonanarduino.Isthistherightwaytogo??

MuchThanks.

Steffano.

olegNovember30,2012at4:04pmReply

Icantseeanyencoderapplicationhere.Yourprojectisquitestraightforward,justcodeyoursensorstatesdirectly.

SteffanoGizzlerDecember1,2012at10:45amReply

HiOleg,

Pleasecouldyoukindlyelaborateonwhatyoumeanbycodingthesensorstatesdirectly?sinceitsasequence.amusingIRsensorswithmakeandbreakbeam.Iwillappreciateanymoreinformation.

Thankyou.Staffano.

SteffanoGizzlerDecember3,2012at11:31amReply

HiOleg,



Thisisthefarhavecomesofarandamserialprintingthecounts.AnyideahowIcouldholdoldvalueandupdatethisoldvaluewiththecurrentvalcounttoa3digitsevensegmentdisplay?dependingonhowthesensorsaretripped?Anycorrectionorsuggestionsamverywillingtolearn

intcounter,S1_SIG=0,S2_SIG=1

voidsetup(){attachInterrupt(0,S1_RISE,RISING)//hookedtopin2onmega2560attachInterrupt(1,S2_RISE,RISING)//hookedtopin3Serial.begin(115200)}//setup

voidloop(){

}

voidS1_RISE(){detachInterrupt(0)S1_SIG=1

if(S2_SIG==0)counter++//entryif(S2_SIG==1)counter//exitSerial.println(counter)attachInterrupt(0,S1_FALL,FALLING)}

voidS1_FALL(){detachInterrupt(0)S1_SIG=0

if(S2_SIG==1)counter++//entryif(S2_SIG==0)counter//exitSerial.println(counter)attachInterrupt(0,S1_RISE,RISING)}





Steffano



steffanoDecember27,2012at4:36pmReply

Imanagedtodomy2ISRforthetwosensorsandthe3digitsevensegmentdisplay,howevertheonlyproblemhavegotiswhenmysensorsarebrokenatfirstthecountgoesnegativefor2or3cyclesthen

comestopositive(normal)doesanyonehaveanideahowtocorrectthis??please.Ihavedeclaredstaticintiinloop.

WindsorFebruary1,2013at8:53pmReply

Hi,thanksforthegreattutorial.Iadaptedyourcode(withminorchanges)torunonanSTM32F100B(ARM)micro.Worksflawlesslywithmyencoderwithouttheneedforanyhardwaredebouncingcircuitry!

JoshFebruary23,2013at9:03pmReply

HiMr.Oleg,Gooddaytoyouandthanksforthegreatefforthelpingarookielikemetostartwiththearduino,Ihave

triedyourcodeusingUnoanditworksflawlesslybutwhenitrieditusingtheLeonardo,itdidntwork,wanderingwhatcouldbetheproblem.

JoshFebruary23,2013at10:14pmReply

HiMr.Oleg,BelowisthecodeIusedwithUnoandLeonardo,itworkswithUnobutnotwithLeonardo.

/*Rotaryencoderreadexample*/#defineENC_A14#defineENC_B15#defineENC_PORTPINC//constantswontchange.Theyreusedhereto//setpinnumbers:constintbuttonPin=2//thenumberofthepushbuttonpinconstintledPin=13//thenumberoftheLEDpin

//variableswillchange:intbuttonState=0//variableforreadingthepushbuttonstatusintswitch0=0voidsetup(){/*Setupencoderpinsasinputs*/pinMode(ENC_A,INPUT)digitalWrite(ENC_A,HIGH)pinMode(ENC_B,INPUT)digitalWrite(ENC_B,HIGH)

//initializeserialcommunicationat9600bitspersecond:Serial.begin(115200)Serial.println(Start)delay(1)//initializetheLEDpinasanoutput:pinMode(ledPin,OUTPUT)//initializethepushbuttonpinasaninput:pinMode(buttonPin,INPUT)}

voidloop(){staticuint8_tcounter=0//thisvariablewillbechangedbyencoderinputint8_ttmpdata/**/tmpdata=read_encoder()if(tmpdata){



Serial.print(Countervalue:)Serial.println(counter,DEC)counter+=tmpdata}//readthestateofthepushbuttonvalue:buttonState=digitalRead(buttonPin)

//checkifthepushbuttonispressed.//ifitis,thebuttonStateisHIGH:if(buttonState==LOW){//turnLEDon:digitalWrite(ledPin,HIGH)//printoutthestateofthebutton:if(switch0==0){Serial.print(Pinindot)delay(1)Serial.println(buttonState)delay(1)//delayinbetweenreadsforstabilityswitch0=1}}else{//turnLEDoff:digitalWrite(ledPin,LOW)if(switch0==1){Serial.print(Pinindot)delay(1)Serial.println(buttonState)delay(1)//delayinbetweenreadsforstabilityswitch0=0}}}

/*returnschangeinencoderstate(1,0,1)*/int8_tread_encoder(){staticint8_tenc_states[]={0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0}staticuint8_told_AB=0/**/old_AB



alwernerMarch14,2013at9:47amReply

UsingtwoormoreencoderwiththeArduino?

ItalldependsonthetotaloftasksbeingperformedbytheArduino,andthenumberofpulsesreceivedbytheprocessor.

Sayforexampleyouhaveasmallslowmovingxytable,with2rotaryUSDigitalencodersgeneratingsay4000pulsespersecondanddrivingtwosteppermotorswithanEasydriverboardyouwouldsoonberunningoutofheadroomonyourproject.

Mysuggestionswouldbetouse,twoTiny13chipsfromAtmeltoencodetherotaryencoders,andthanfeedtheresultantsignalintoyourArduino,whereitwillgiveanexcellentperformance.Inmyhumbleopnionitmayevensupportthreechannels,XYandZ.

Youwouldneedsomemachinecodeexperiencetodothis,butthiswouldbeworthlearning.

Goodluck.

SeifApril6,2013at1:04pmReply

Hi,

ThankyouforthisgreatusefularticleImwonderingifIcanuseyouideawithArduinoUno??ImeantousetherotaryencoderwithArduinoUnoinordertoselectthepowerofmyRCcarwhichImbuilding

thanxagain

olegApril6,2013at1:26pmReply

UNOshouldwork.

SalvatoreAielloApril15,2013at12:49pmReply

Hi,Sweetbitofcode!Iamusingitinaprojectatwork,usingtheencodertodisplayamotorspeedselection

onasevensegmentdisplayanditworksverynicelyindeed.Onceyouremovetheserial.printcommandsitisdifficulttospinthebareencodershaftquicklyenoughtogenerateamisread.Withasuitablysizedknobontheshaftitisgoingtoslowrotationspeedandmakeitvirtuallyimpossibleforthecasualoperatortogetanerroneousreading

Thanks!

MarcoAugust1,2013at1:23pmReply

Hi,verynicejobmyR2D2Domesencodersensorhas3output,oneofthemreadsjustonespecialdentonthemotor

gear,likeaZEROPOSITION.HowcanIimplementitinthecode?AlsoHowcanImakeencoderscountto36or+18to18?Thanksjustlearninghere

AlexAugust14,2013at9:48amReply

Hereisthecodewithzeropositionand3outputs.

intcounter,S1_SIG=0,S2_SIG=1,S3_SIG=1



boolfirstinit=false

voidsetup(){attachInterrupt(0,S1_RISE,RISING)//hookedtopin2onmega2560attachInterrupt(1,S2_RISE,RISING)//hookedtopin3attachInterrupt(2,S3_RISE,RISING)//hookedtopin21Serial.begin(115200)}//setup

voidloop(){

}






if(S1_SIG==1)counter++//entryif(S1_SIG==0)counter//exit//Serial.println(counter)attachInterrupt(1,S2_FALL,FALLING)}





voidS3_RISE(){S3_SIG=1detachInterrupt(2)

if(!firstinit&&((S2_SIG==1&&S1_SIG==1)||(S1_SIG==0&&S2_SIG==1))){counter=0firstinit=true}

attachInterrupt(2,S3_FALL,FALLING)}

voidS3_FALL(){S3_SIG=0detachInterrupt(2)

if(!firstinit&&((S2_SIG==1&&S1_SIG==1)||(S1_SIG==1&&S2_SIG==0))){counter=0firstinit=true}

attachInterrupt(2,S3_RISE,RISING)}

MartyAugust30,2013at9:31pmReply

IamnewtoArduinosandamstartingtoplaywiththem.Ihaveseenmanyexamplesofrotaryencodercode.ButnonthatusetheLeonardotooutputkeypresscommandswhenrotated.Myapplicationisa

smallCNCverticalmachiningcenter.Thecontrolitselfcannotacceptarotaryencoder(manualpulsegenerator)ThecontrolisPCbased.ItCANacceptkeypresses,forexample,tomovethetableinthesedirections:X+Ctrl+RightArrowKeyXCtrl+LeftArrowKeyY+Ctrl+UpArrowKeyYCtrl+DownArrowKeyZ+Ctrl+PageUpKeyZCtrl+PageDownKeyA+Ctrl+Plus(+)KeyACtrl+Minus()Key

IcanmakeitworkwithoutaCtrlkeypress,butbettertohavethecombinationifpossible.Iwasthinkingofusinga4positionrotaryswitch.Eachpositionwouldbeforeachaxis,X,Y,ZandA.Whentheswitchisintheproperposition,thendependingonwhichdirectiontheMPGhandwheelwasturned,LeonardowouldsendtheappropriatekeyboardcharacterviathePCsUSBport.OnekeypressforeachpulseoftheMPGhandwheel.Itisa100PPRhandwheel.

Isthisdoableandmightsomeonebeabletohelpcutmylearningcurvedownwithanexampleofthecode?Thanks!

faultymonkSeptember15,2013at10:19pmReply

JustasanotetopeopletryingtouseaLeonardo(orMicro),thecodeexamplewillworkifyouuse:

#defineENC_AA4#defineENC_BA5#defineENC_PORTPINF



olegSeptember15,2013at10:37pmReply

Thanks!

RonSeptember17,2013at4:06amReply

Youmentionthis:Sparkfunencoder,youllnoticethatitgives4incrementsperclickanditsimpossibletomakeithold

positionbetweenclicks.Therefore,tocountclicksyouwillneedtodividecountervariableby4

MyQuadratureencodersaregiving2countsperclick.Wouldyoumindaquicklessononjusthowtodothis,sincethevariableisntadecimalnumber?

Manythanks!Yourcodeisforcingmetodiginandlearnmorethanjustthesimpleprogramming,asgivenontheArduinositeexampleswhichiswhatteachingisallabout!

olegSeptember17,2013at9:33amReply

Dowhatdivideby2?Thefastestwayistorightshiftonce.

RonSeptember17,2013at8:06pmReply

Igotitoneofthosedoh!momentssorry!

RonSeptember18,2013at12:48pmReply

(withregardtothesolutionfor24posencoderwhichgives2pulsesperclick)

WhathappenswhenIbitwiseshift(1bit)rightanegativenumber,aswhenImturningCCW?Doesthesignbitstaywhereitssupposedto?

ImgettingverydifferentresultsCWfromCCW.


Youdontshiftnumbers,youshiftbytes.Whenyourightshifttheleftmostbitbecomeszero.Ifthisbitrepresentedasign,itwillbegone.


Ifyourencoderclickseverysecondpulseyoucandetermineaclickpositionwithoutdividing.Evenincrementswillhavezeroinbit0andoddincrementswillhaveone.Thisistrueforbothsignedand

unsignedrepresentations.Also,checkingsinglebit,likeif(count&0x01){...,couldbefasterthanshifting.

fbonanOctober3,2013at7:46amReply

ThanksOleg,thissampleisgreatandsavemeyears:)Manyrequestedacompleteworkingexamplewith2encoders,hereitis:



#defineENC_1_AA0#defineENC_1_BA1

#defineENC_2_AA2#defineENC_2_BA3

intencoder_1_value=0intencoder_2_value=0

staticint8_tenc_states[]={0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0}

voidsetup(){/*Setupencoderpinsasinputs*/pinMode(ENC_1_A,INPUT)digitalWrite(ENC_1_A,HIGH)pinMode(ENC_1_B,INPUT)digitalWrite(ENC_1_B,HIGH)

/*Setupencoderpinsasinputs*/pinMode(ENC_2_A,INPUT)digitalWrite(ENC_2_A,HIGH)pinMode(ENC_2_B,INPUT)digitalWrite(ENC_2_B,HIGH)

Serial.begin(115200)Serial.println(************Start*************)}

/*returnschangeinencoderstate(1,0,1)*/int8_tread_encoder1(){staticuint8_told_AB=0

old_AB



Fabrice

BrettOctober25,2014at4:13pmReply

Forsomereasonyourcodeworkedformewhenolegswouldnot.Thankyouforpostingit!

prinsNovember2,2013at2:28pmReply

greattutorial.

IfoundHIDboardusingPIC18F4550chipcapableofreading16rotaryencoders(alltypesofrotary)inrealtime,andnoadditionalchip.anyoneknowshowtodothatinarduino.whatmethodisitimplementing,timerorinterrupt?

markNovember14,2013at4:09amReply

howcanIusethiscodeonmega2560.Igetserialtoprintstartbutthatsit.WhatpinedoIuse?


For2560,youdontneedtodoanything,thepinsareswitchedinthecodeduringcompile.

markNovember20,2013at1:29amReply

Thanks,

SoImusinganalogpins14and15butgetnoresponsefromtheencoder.Tried14and15Digital,noresponse.

IfyoudliketomoveencoderpinstoArduinopins8and9,ENC_PORTshallbedefinedasPINB,andforpins0,1asPIND.

whydoesENC_PORTchangewhenchangingpins,isthisuniquetotheboardyourusing?

whatsENC_PORTdo?

OlegMazurovNovember20,2013at9:18amReply

ENC_PORTisa#defineforaportname.DoesitworkifyoureusingthesamepinsasI?

JayOctober7,2014at8:57pm

HiOleg,IalsohavethesameproblemwithaMEGA256,Idontgetresponsefromtheencoder.

TriedchangingENC_PORTtoPINBPINCandPIND,noneofthemwork.Anyidea?



OlegMazurovOctober7,2014at10:48pm

Makesureyourencoderisconnectedtotheportyoursketchisreading,portbits0and1.

JayOctober8,2014at1:31pm

Yes,itsproperlywiredandconnectedtotherightpins

OlegMazurovOctober8,2014at1:48pm

Itshouldworkthen,butitdoesnt.Maybeyourtestingneedstobechanged?IncludetheArduinoitself.Forexample,makesureyoucanreadasingepin.

Connectapushbuttontoadatapinandwriteasketchwhichreadsthestateofthispinandprintsitout.Therearemanyexamplesonthenetdoingsimilarthings.Thenmovethebuttontooneofthepinsintendedfortheencoderandmakeitworkthere,thenmovetotheotherpin.Thenconnecttheencoder,itsreallyapairofpushbuttonswithsomecleversequencer.Thenmodifymysketchwithwhatyouhavelearneditwillwork.

PostagoodpictureofyoursetuptotheaccompanyingG+communitysothatotherpeoplecanseeitandhelpyoutoo>https://plus.google.com/u/0/communities/113627505540902841340

AllanNovember25,2013at4:18amReply

isitpossobletomeasurewheelspeedusingarotaryencoderincrementalwithoutputA,BanZ

OlegMazurovNovember25,2013at9:16amReply

Yesbutyouwillneeddifferentlookuptable.

adityaDecember10,2013at5:36amReply

Ihave12V,500RPM,15KgcmDCgearedmotorandencoder.HowcouldIcontroltheDCmotortorotateinforward,ReversedirectionandNoofrotationsofDCmotorshaft.

MikeKehrliDecember18,2013at12:53pmReply

HiOleg,

IadaptedthiscodetoaPICchipprojectIwas/amworkingonmanymonthsago.Itmademyrotaryknobfunctionalityperfectlycleanforthefirsttime.Thecodewasmorecompactaswell.Ineverdidmentionit,butthiswasreallyhelpfultome.Itworksveryverywellonarotaryencoderwithabsolutelynohardwaredebouncing.Thesignalisreallyugly.

Justwantedtosaythanks.Ivetriedlotsofdebouncecode.ThisisnotonlythebestIvefound,butthebestbyfar.

LiamGoudgeDecember22,2013at3:46amReply

HiOleg.



Whatanelegantalgorithmread_encoderisaverynicewaytoimplementthestatemachine.Thanksforpublishingandsharingyourideas.VerysimpleporttotheFreescaleplatformonARMsMBED.WorkedverywellbutIdidneed100nFofantibounceonmyPanasonicEVEKE2F2024Bencoder,perhapsbecausethisCPUisclockedsomuchfasterthantheATMEGAandAVRs.

JeffBeougherFebruary16,2014at10:13amReply

Iamattemptingtoconnect6encoderstoanArduinoLeonardowithaMCP23017I2cPortExpander.IhavebeenabletouseoneencoderontheArduinodirectly.WhatIamattemptingtodoisdependingifthe

encoderisturnedupordowntosendakeyboardscankeytotothecomputerforaproject.Iwashopingtohavesometypeofmultiplexingtobeabletoreadeachencoderandknowiftheyhavebeenturned.TheMCP23017hasnothelped.IknowitworksbecauseIhavebeenabletousetheexamplecodesandblinkanledandseebuttonpressinput.

SomyquestionishowcanImultiplex6rotaryencoders.EitherusingtheMCP23017oradifferentinputexpanderofsometype.

LinkstotheencoderandMCP.

http://www.adafruit.com/products/377http://www.adafruit.com/products/732

NeelamApril17,2014at10:55amReply

Hi,

Myprojectistocontrolthespeedofthedcmotor(Hardware)usingPIDcontrollerinLabVIEW.ForinterfacingLabviewwithdcmotor,IamusingArduinoUno.Forencoder,IamusingOptocouplerandaschmitttrigger.Theencoderhasthreeterminals.Redbrown&black.redandblackarefor+5vandgroundrespectivelyandbrownwillreadthevalue(i.eno.ofrotations)fromthedcmotor.Thisoutputshouldbeconnectedtoarduinowhichinturnwillpassthisvaluetolabview.PleasetellmeonwhichpinofarduinoIshouldconnectthatbrownwire.

Fromdigitalpin3ofarduino,IampassingPWMsignaltothedcmotor.Itriedtoconnectthatbrownwireofencodertopin5butIamgettinganunknownerror.

Pleasehelpmeinthis.

peterJanuary17,2015at11:22pmReply

HiOleg.thanksforyourdemonstration.

RobertMarch28,2015at1:34pmReply

ThanksOleg,yourcodeworksgreatontheSparkfunilluminatedRGBencoders.

TogetittoworkonmyMEGA2560,IusedA0andA1,changingthedefinitionsto:#defineENC_AA0#defineENC_BA1#defineENC_PORTPINF

HermanMarch30,2015at5:35pmReply

IamnewatArduino(Uno)andwritingcodesothisisagoodexampleforme.ThanksOleg!Ihaveabagofencodersthatseemtoworkdifferent.IputsomeLEDsontheterminalstoseehowthey



work.Whenturningclockwisebothoutputsbecomehighsimiltanious,thenonegoeslowandthentheothergoeslow.Whenturningcounter/anticlockwisethefirstonebecomeshigh,thenthesecondoneandthentheybothgetlowatthesametime.Likethis:010010010011011011

IsthereaneasywayIcanchangethiscodesomyrotaryencoderswillwork?Ihopeyoucanhelpme.

OlegMazurovMarch30,2015at6:25pmReply

Imnotsureabouteasyway.ThefundamentalpropertyofGreycodeencoderisthatonlyoneoutputischangingatatimesothatwhenbothhaschangedsimultaneouslyyouwouldknowthat

theoutputsarewrongsomehow.Youcanchangethelookuptabletogiveproperincrement/decrementforyoursequencebutthenyoudhavetoaddadebounce.

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